Isolation and characterization of the circulating form of human endostatin.
Recently, fragments of extracellular proteins, including endostatin, were defined as a novel group of angiogenesis inhibitors. In this study, human plasma equivalent hemofiltrate was used as a source for the purification of high molecular weight peptides (10-20 kDa), and the isolation and identification of circulating human endostatin are described. The purification of this C-terminal fragment of collagen alpha1(XVIII) was guided by MALDI-MS and the exact molecular mass determined by ESI-MS was found to be 18 494 Da. N-terminal sequencing revealed the identity of this putative angiogenesis inhibitor and its close relation to mouse endostatin. The cysteine residues 1-3 and 2-4 in the molecule are linked by disulfide bridges. In vitro biological characterization of the native protein demonstrated no anti-proliferative activity on different endothelial cell types. These data indicate that human endostatin, which is a putative angiogenesis inhibitor, is present in the circulation.
Ständker
L
L
Lower Saxony Institute for Peptide Research (IPF), Hannover, Germany.
Schrader
M
M
Kanse
S M
SM
Jürgens
M
M
Forssmann
W G
WG
Preissner
K T
KT
D000595:Amino Acid Sequence; D002452:Cell Count / Q000187:drug effects; D003094:Collagen / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D043170:Collagen Type XVIII; D043169:Endostatins; D004730:Endothelium, Vascular / Q000187:drug effects; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006440:Hemofiltration; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D018919:Neovascularization, Physiologic; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D043170:Collagen Type XVIII; D043169:Endostatins; D010446:Peptide Fragments; D016222:Fibroblast Growth Factor 2; D003094:Collagen